Carbonaceous Species of PM2.5 in Megacity Delhi, India During 2012–2016

Abstract

Organic carbon (OC) and elemental carbon (EC) in PM2.5 were estimated to study the seasonal and inter-annual variability of atmospheric total carbonaceous aerosols (TCA) at an urban site of megacity Delhi, India for 5 years from January, 2012 to December, 2016. The annual average (± standard deviation) concentrations of PM2.5, OC, EC and TCA were 128 ± 81, 16.6 ± 12.2, 8.4 ± 5.8 and 34.5 ± 25.2 µg m−3, respectively. During the study, significant seasonal variations in mass concentrations of PM2.5, OC, EC and TCA were observed with maxima in winter and minima in monsoon seasons. Significant correlations between OC and EC, and OC/EC ratio suggested that vehicular emissions, fossil fuel combustion and biomass burning could be major sources of carbonaceous aerosols of PM2.5 at the sampling site of Delhi, India.

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Acknowledgements

The authors are thankful to the Director, CSIR-NPL, New Delhi and Head, Environmental Sciences & Biomedical Metrology Division (ES&BMD), CSIR-NPL, New Delhi for their encouragement. The authors also acknowledge the Ministry of Environment Forest and Climate Change (MoEFCC), New Delhi for providing partial financial support for this study (GAP-161632 Project).